Week 15

Your growing baby now measures about 4 inches long, crown to rump, and weighs in at about 2 1/2 ounces (about the size of an apple). He's busy moving amniotic fluid through her nose and upper respiratory tract, which helps the primitive air sacs in his lungs begin to develop. His legs are growing longer than his arms now, and he can move all of his joints and limbs. Although his eyelids are still fused shut, he can sense light. If you shine a flashlight at your tummy, for instance, he's likely to move away from the beam. There's not much for your baby to taste at this point, but he is forming taste buds.

Ossification begins this week. This means that the mini bones in your baby's body will begin hardening. The face is becoming more defined with each passing day and he is gaining weight and length quickly!